Since LCD is a non-self-emissive display, a back light unit (BLU) is designed to be a light source of a LCD and will consumes about 50˜70% of battery power of a portable 3C device depending on the nature and design of the devices.
A conventional LCD functions by utilizing a polarized light switching mechanism to display images. Polarization occurs as natural light passes through a polarizer, which absorbs one of the polarization states and pass through the other polarization state of the light. In this process, substantially more than half of the incident light is absorbed by the absorptive polarizer. This makes a system low in energy efficiency.